In a prospective study, we evaluated hematological parameters in freshly obtained venous blood samples from 632 Sudanese patients attending the outpatient department at Khartoum Teaching Hospital, Khartoum, Sudan, in the period between March and July 2005. The patients were surveyed for full blood count (FBC) and hemoglobin (Hb) electrophoresis using a cellulose acetate method. Hb S [beta6(A3)Glu-->Val] was the most common abnormal Hb, which was not unexpected because the subjects live in the center of a malaria-affected area. The study showed low hematological parameters due to various causes including poor nutrition as well as infections and hemolytic processes.